Problem: If $x \otimes y = x+3y$ and $x \triangleright y = 4x-7$, find $(-4 \triangleright -5) \otimes -3$.
First, find $-4 \triangleright -5$ $ -4 \triangleright -5 = (4)(-4)-7$ $ \hphantom{-4 \triangleright -5} = -23$ Now, find $-23 \otimes -3$ $ -23 \otimes -3 = -23+(3)(-3)$ $ \hphantom{-23 \otimes -3} = -32$.